1. Field of the Invention
This invention relates to an expanding fixture for securing an element to a wall or ceiling by securing the element to a bore in the wall or ceiling.
More specifically the invention is concerned with the use of an expanding fixture to secure the element in a bore. The element includes a socketed part to be driven into the wall ceiling, and is associated with an expanding piece which is composed of flat material which penetrates into the socket piece. The expanding piece is arranged with a tapered section to widen the socket and press the socket against the wall of the bore. The expanding piece also includes a part which projects beyond the socket diameter on a side opposite to the bore base, and this is situated in a longitudinal slot of the socket and is arranged so that it can be supported on the edge of the bore.
2. Description of the Prior Art
One type of such expanding fixture is known from German Pat. No. 2,135,333. This known expanding fixture does not require or use the base of the bore to support the expanding piece, and therefore, the bore may accidentally be made deeper than necessary. The elements which are to be fixed in the wall or ceiling are secured on the expanding piece in this known expanding fixture; the expanding piece has special holding means e.g. an integral hook, for this purpose which projects from the socket eccentrically out of a longitudinal slot thereof. In order to secure a hollow section such as, for example a tube, onto the hook of the expanding piece, a great deal of work is involved; and, after screwing or welding thereon, the hold achieved is not firm enough for high torques to be absorbed. The reason for this is that the end of the expanding piece which is composed of flat material projecting out of the bore can be bent transversely and can mainly be put under tension parallel to the bore axis. As the expanding piece is only supported on the edge of the bore on one side, the expanding piece including the socket can tilt, while the socket is being driven in and therefore be set off-center after the socket has been driven in. This is particularly so when the bore is slightly too large. Furthermore, a bore which is too shallow can lead to a strong jolting of the conical, undulating section of the expanding part so that the socket no longer laterally passes the inner end of the expanding part.
It is known from German Pat. No. 1,110,113 to provide slots at the end of a rod and introduce an expanding piece formed from a cylindrical part into the slots. This expanding piece is supported on the floor of the bore while the rod is being driven in so that a bore hole which has been drilled too deeply does not provide a fixture which is exact in measurement. The production of the aforesaid solid expanding piece is moreover quite costly.